BaseNCodec (Encode/Decode Utilities (Version 1.9))

java.lang.Object
- org.apache.commons.codec.binary.BaseNCodec

All Implemented Interfaces:

BinaryDecoder, BinaryEncoder, Decoder, Encoder

Direct Known Subclasses:

Base32, Base64
```
public abstract class BaseNCodec
extends java.lang.Object
implements BinaryEncoder, BinaryDecoder
```
Abstract superclass for Base-N encoders and decoders.
This class is thread-safe.

Version:

$Id: BaseNCodec.java 1465182 2013-04-06 04:03:12Z ggregory $

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

(package private) static class BaseNCodec.Context
Holds thread context so classes can be thread-safe.

Nested Classes
Modifier and Type	Class and Description
`(package private) static class`	`BaseNCodec.Context` Holds thread context so classes can be thread-safe.

Field Summary

Fields
Modifier and Type	Field and Description
`private int`	`chunkSeparatorLength` Size of chunk separator.
`private static int`	`DEFAULT_BUFFER_RESIZE_FACTOR`
`private static int`	`DEFAULT_BUFFER_SIZE` Defines the default buffer size - currently 8192 - must be large enough for at least one encoded block+separator
`private int`	`encodedBlockSize` Number of bytes in each full block of encoded data, e.g.
`(package private) static int`	`EOF` EOF
`protected int`	`lineLength` Chunksize for encoding.
`protected static int`	`MASK_8BITS` Mask used to extract 8 bits, used in decoding bytes
`static int`	`MIME_CHUNK_SIZE` MIME chunk size per RFC 2045 section 6.8.
`protected byte`	`PAD`
`protected static byte`	`PAD_DEFAULT` Byte used to pad output.
`static int`	`PEM_CHUNK_SIZE` PEM chunk size per RFC 1421 section 4.3.2.4.
`private int`	`unencodedBlockSize` Number of bytes in each full block of unencoded data, e.g.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`BaseNCodec(int unencodedBlockSize, int encodedBlockSize, int lineLength, int chunkSeparatorLength)` Note `lineLength` is rounded down to the nearest multiple of `encodedBlockSize` If `chunkSeparatorLength` is zero, then chunking is disabled.

Method Summary

Methods
Modifier and Type	Method and Description
`(package private) int`	`available(BaseNCodec.Context context)` Returns the amount of buffered data available for reading.
`protected boolean`	`containsAlphabetOrPad(byte[] arrayOctet)` Tests a given byte array to see if it contains any characters within the alphabet or PAD.
`byte[]`	`decode(byte[] pArray)` Decodes a byte[] containing characters in the Base-N alphabet.
`(package private) abstract void`	`decode(byte[] pArray, int i, int length, BaseNCodec.Context context)`
`java.lang.Object`	`decode(java.lang.Object obj)` Decodes an Object using the Base-N algorithm.
`byte[]`	`decode(java.lang.String pArray)` Decodes a String containing characters in the Base-N alphabet.
`byte[]`	`encode(byte[] pArray)` Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
`(package private) abstract void`	`encode(byte[] pArray, int i, int length, BaseNCodec.Context context)`
`java.lang.Object`	`encode(java.lang.Object obj)` Encodes an Object using the Base-N algorithm.
`java.lang.String`	`encodeAsString(byte[] pArray)` Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet.
`java.lang.String`	`encodeToString(byte[] pArray)` Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet.
`protected byte[]`	`ensureBufferSize(int size, BaseNCodec.Context context)` Ensure that the buffer has room for `size` bytes
`protected int`	`getDefaultBufferSize()` Get the default buffer size.
`long`	`getEncodedLength(byte[] pArray)` Calculates the amount of space needed to encode the supplied array.
`(package private) boolean`	`hasData(BaseNCodec.Context context)` Returns true if this object has buffered data for reading.
`protected abstract boolean`	`isInAlphabet(byte value)` Returns whether or not the `octet` is in the current alphabet.
`boolean`	`isInAlphabet(byte[] arrayOctet, boolean allowWSPad)` Tests a given byte array to see if it contains only valid characters within the alphabet.
`boolean`	`isInAlphabet(java.lang.String basen)` Tests a given String to see if it contains only valid characters within the alphabet.
`protected static boolean`	`isWhiteSpace(byte byteToCheck)` Checks if a byte value is whitespace or not.
`(package private) int`	`readResults(byte[] b, int bPos, int bAvail, BaseNCodec.Context context)` Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail bytes.
`private byte[]`	`resizeBuffer(BaseNCodec.Context context)` Increases our buffer by the `DEFAULT_BUFFER_RESIZE_FACTOR`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - EOF
```
static final int EOF
```
    EOF
    
    Since:
    
    1.7
    
    See Also:
    Constant Field Values
  - MIME_CHUNK_SIZE
```
public static final int MIME_CHUNK_SIZE
```
    MIME chunk size per RFC 2045 section 6.8.
    The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    RFC 2045 section 6.8, Constant Field Values
  - PEM_CHUNK_SIZE
```
public static final int PEM_CHUNK_SIZE
```
    PEM chunk size per RFC 1421 section 4.3.2.4.
    The 64 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.
    
    See Also:
    RFC 1421 section 4.3.2.4, Constant Field Values
  - DEFAULT_BUFFER_RESIZE_FACTOR
```
private static final int DEFAULT_BUFFER_RESIZE_FACTOR
```
    See Also:
    Constant Field Values
  - DEFAULT_BUFFER_SIZE
```
private static final int DEFAULT_BUFFER_SIZE
```
    Defines the default buffer size - currently 8192 - must be large enough for at least one encoded block+separator
    
    See Also:
    Constant Field Values
  - MASK_8BITS
```
protected static final int MASK_8BITS
```
    Mask used to extract 8 bits, used in decoding bytes
    
    See Also:
    Constant Field Values
  - PAD_DEFAULT
```
protected static final byte PAD_DEFAULT
```
    Byte used to pad output.
    
    See Also:
    Constant Field Values
  - PAD
```
protected final byte PAD
```
    See Also:
    Constant Field Values
  - unencodedBlockSize
```
private final int unencodedBlockSize
```
    Number of bytes in each full block of unencoded data, e.g. 4 for Base64 and 5 for Base32
  - encodedBlockSize
```
private final int encodedBlockSize
```
    Number of bytes in each full block of encoded data, e.g. 3 for Base64 and 8 for Base32
  - lineLength
```
protected final int lineLength
```
    Chunksize for encoding. Not used when decoding. A value of zero or less implies no chunking of the encoded data. Rounded down to nearest multiple of encodedBlockSize.
  - chunkSeparatorLength
```
private final int chunkSeparatorLength
```
    Size of chunk separator. Not used unless lineLength > 0.
- Constructor Detail
  - BaseNCodec
```
protected BaseNCodec(int unencodedBlockSize,
          int encodedBlockSize,
          int lineLength,
          int chunkSeparatorLength)
```
    Note lineLength is rounded down to the nearest multiple of encodedBlockSize If chunkSeparatorLength is zero, then chunking is disabled.
    
    Parameters:
    unencodedBlockSize - the size of an unencoded block (e.g. Base64 = 3)
    encodedBlockSize - the size of an encoded block (e.g. Base64 = 4)
    lineLength - if > 0, use chunking with a length lineLength
    chunkSeparatorLength - the chunk separator length, if relevant
- Method Detail
  - hasData
```
boolean hasData(BaseNCodec.Context context)
```
    Returns true if this object has buffered data for reading.
    
    Parameters:
    context - the context to be used
    
    Returns:
    true if there is data still available for reading.
  - available
```
int available(BaseNCodec.Context context)
```
    Returns the amount of buffered data available for reading.
    
    Parameters:
    context - the context to be used
    
    Returns:
    The amount of buffered data available for reading.
  - getDefaultBufferSize
```
protected int getDefaultBufferSize()
```
    Get the default buffer size. Can be overridden.
    
    Returns:
    DEFAULT_BUFFER_SIZE
  - resizeBuffer
```
private byte[] resizeBuffer(BaseNCodec.Context context)
```
    Increases our buffer by the DEFAULT_BUFFER_RESIZE_FACTOR.
    
    Parameters:
    context - the context to be used
  - ensureBufferSize
```
protected byte[] ensureBufferSize(int size,
                      BaseNCodec.Context context)
```
    Ensure that the buffer has room for size bytes
    
    Parameters:
    size - minimum spare space required
    context - the context to be used
  - readResults
```
int readResults(byte[] b,
              int bPos,
              int bAvail,
              BaseNCodec.Context context)
```
    Extracts buffered data into the provided byte[] array, starting at position bPos, up to a maximum of bAvail bytes. Returns how many bytes were actually extracted.
    Package protected for access from I/O streams.
    
    Parameters:
    b - byte[] array to extract the buffered data into.
    bPos - position in byte[] array to start extraction at.
    bAvail - amount of bytes we're allowed to extract. We may extract fewer (if fewer are available).
    context - the context to be used
    
    Returns:
    The number of bytes successfully extracted into the provided byte[] array.
  - isWhiteSpace
```
protected static boolean isWhiteSpace(byte byteToCheck)
```
    Checks if a byte value is whitespace or not. Whitespace is taken to mean: space, tab, CR, LF
    
    Parameters:
    byteToCheck - the byte to check
    
    Returns:
    true if byte is whitespace, false otherwise
  - encode
```
public java.lang.Object encode(java.lang.Object obj)
                        throws EncoderException
```
    Encodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].
    
    Specified by:
    
    encode in interface Encoder
    
    Parameters:
    obj - Object to encode
    
    Returns:
    An object (of type byte[]) containing the Base-N encoded data which corresponds to the byte[] supplied.
    
    Throws:
    
    EncoderException - if the parameter supplied is not of type byte[]
  - encodeToString
```
public java.lang.String encodeToString(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a String containing characters in the Base-N alphabet. Uses UTF8 encoding.
    
    Parameters:
    pArray - a byte array containing binary data
    
    Returns:
    A String containing only Base-N character data
  - encodeAsString
```
public java.lang.String encodeAsString(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a String containing characters in the appropriate alphabet. Uses UTF8 encoding.
    
    Parameters:
    pArray - a byte array containing binary data
    
    Returns:
    String containing only character data in the appropriate alphabet.
  - decode
```
public java.lang.Object decode(java.lang.Object obj)
                        throws DecoderException
```
    Decodes an Object using the Base-N algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[] or String.
    
    Specified by:
    
    decode in interface Decoder
    
    Parameters:
    obj - Object to decode
    
    Returns:
    An object (of type byte[]) containing the binary data which corresponds to the byte[] or String supplied.
    
    Throws:
    
    DecoderException - if the parameter supplied is not of type byte[]
  - decode
```
public byte[] decode(java.lang.String pArray)
```
    Decodes a String containing characters in the Base-N alphabet.
    
    Parameters:
    pArray - A String containing Base-N character data
    
    Returns:
    a byte array containing binary data
  - decode
```
public byte[] decode(byte[] pArray)
```
    Decodes a byte[] containing characters in the Base-N alphabet.
    
    Specified by:
    
    decode in interface BinaryDecoder
    
    Parameters:
    pArray - A byte array containing Base-N character data
    
    Returns:
    a byte array containing binary data
  - encode
```
public byte[] encode(byte[] pArray)
```
    Encodes a byte[] containing binary data, into a byte[] containing characters in the alphabet.
    
    Specified by:
    
    encode in interface BinaryEncoder
    
    Parameters:
    pArray - a byte array containing binary data
    
    Returns:
    A byte array containing only the basen alphabetic character data
  - encode
```
abstract void encode(byte[] pArray,
          int i,
          int length,
          BaseNCodec.Context context)
```
  - decode
```
abstract void decode(byte[] pArray,
          int i,
          int length,
          BaseNCodec.Context context)
```
  - isInAlphabet
```
protected abstract boolean isInAlphabet(byte value)
```
    Returns whether or not the octet is in the current alphabet. Does not allow whitespace or pad.
    
    Parameters:
    value - The value to test
    
    Returns:
    true if the value is defined in the current alphabet, false otherwise.
  - isInAlphabet
```
public boolean isInAlphabet(byte[] arrayOctet,
                   boolean allowWSPad)
```
    Tests a given byte array to see if it contains only valid characters within the alphabet. The method optionally treats whitespace and pad as valid.
    
    Parameters:
    arrayOctet - byte array to test
    allowWSPad - if true, then whitespace and PAD are also allowed
    
    Returns:
    true if all bytes are valid characters in the alphabet or if the byte array is empty; false, otherwise
  - isInAlphabet
```
public boolean isInAlphabet(java.lang.String basen)
```
    Tests a given String to see if it contains only valid characters within the alphabet. The method treats whitespace and PAD as valid.
    
    Parameters:
    basen - String to test
    
    Returns:
    true if all characters in the String are valid characters in the alphabet or if the String is empty; false, otherwise
    See Also:
    isInAlphabet(byte[], boolean)
  - containsAlphabetOrPad
```
protected boolean containsAlphabetOrPad(byte[] arrayOctet)
```
    Tests a given byte array to see if it contains any characters within the alphabet or PAD. Intended for use in checking line-ending arrays
    
    Parameters:
    arrayOctet - byte array to test
    
    Returns:
    true if any byte is a valid character in the alphabet or PAD; false otherwise
  - getEncodedLength
```
public long getEncodedLength(byte[] pArray)
```
    Calculates the amount of space needed to encode the supplied array.
    
    Parameters:
    pArray - byte[] array which will later be encoded
    
    Returns:
    amount of space needed to encoded the supplied array. Returns a long since a max-len array will require > Integer.MAX_VALUE

Class BaseNCodec

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EOF

MIME_CHUNK_SIZE

PEM_CHUNK_SIZE

DEFAULT_BUFFER_RESIZE_FACTOR

DEFAULT_BUFFER_SIZE

MASK_8BITS

PAD_DEFAULT

PAD

unencodedBlockSize

encodedBlockSize

lineLength

chunkSeparatorLength

Constructor Detail

BaseNCodec

Method Detail

hasData

available

getDefaultBufferSize

resizeBuffer

ensureBufferSize

readResults

isWhiteSpace

encode

encodeToString

encodeAsString

decode

decode

decode

encode

encode

decode

isInAlphabet

isInAlphabet

isInAlphabet

containsAlphabetOrPad

getEncodedLength